Using multiple control paths, Using multiple control paths for path failover, Using – Dell TL2000 User Manual
Page 42: Multiple, Logical, Libraries, Library, Sharing, Control, Paths
Using
Multiple
Logical
Libraries
for
Library
Sharing
Multiple
logical
libraries
are
an
effective
way
for
the
library
to
simultaneously
back
up
and
restore
data
from
heterogeneous
applications.
For
example,
the
library
can
be
partitioned
so
that
it
processes:
v
Commands
from
Application
A
(about
Department
X)
in
Logical
Library
1
v
Commands
from
Application
B
(about
Department
Y)
in
Logical
Library
2
In
this
configuration,
the
storage
slots
and
drives
in
each
logical
library
are
dedicated
to
that
library
and
are
not
shared
among
other
libraries.
Commands
issued
by
the
applications
travel
to
the
library
through
two
unique
control
paths.
Thus,
the
data
processing
for:
v
Department
X
is
confined
to
the
storage
slots
and
drives
in
Logical
Library
1
v
Department
Y
is
confined
to
the
storage
slots
and
drives
in
Logical
Library
2
Using
Multiple
Control
Paths
In
addition
to
creating
multiple
logical
libraries,
any
logical
library
can
be
configured
to
have
more
than
one
control
path.
When
configuring
additional
control
paths,
additional
library
sharing
configurations
and
availability
options
are
made
possible.
Access
to
the
logical
library
is
on
a
first-come,
first-served
basis
and
each
control
path
for
a
logical
library
can
accept
commands
while
the
library
is
in
use
by
another
control
path.
By
default,
only
the
first
drive
in
a
logical
library
will
be
LUN-1
enabled.
For
a
particular
logical
library,
you
can
enable
as
many
control
paths
as
there
are
drives
in
that
logical
library.
Using
Multiple
Control
Paths
for
Path
Failover
Command
failures
and
timeouts
are
costly.
You
want
your
library
to
run
smoothly
and
efficiently.
To
ensure
continued
processing,
the
library
offers
an
optional
path
failover
feature
that
enables
the
host
device
driver
to
resend
the
command
to
an
alternate
control
path
for
the
same
logical
library.
With
control
path
failover
installed,
the
alternate
control
path
can
include
another
HBA,
SAN,
or
library
control
path
drive.
The
device
driver
initiates
error
recovery
and
continues
the
operation
on
the
alternate
control
path
without
interrupting
the
application.
The
2U
library
does
not
support
Control
Path
Failover
and
Data
Path
Failover.
As
a
result,
there
should
be
no
license
key
entry
for
″Path
Failover
″
on
the
2U
library.
Path
Failover
is
a
combination
of
two
previous
features:
Control
Path
Failover
(key
entered
at
the
library
user
interface)
and
Data
Path
Failover
(key
entered
at
the
device
driver
interface).
The
Path
Failover
feature
is
available
for
select
LTO
4
tape
drives.
Path
Failover
is
not
supported
for
half
height
drives.
The
Path
Failover
feature
can
be
installed
by
the
customer.
For
more
information
about
using
the
path
failover
feature,
see
the
Dell
PowerVault
TL4000
Failover
Configuration
Guide,
included
with
the
library
documentation
if
purchased
at
point
of
sale
and
with
the
customer
kit
if
purchased
later.
3-2
Dell
PowerVault
TL2000
Tape
Library
and
TL4000
Tape
Library
User's
Guide